THE BALANCED CRESCOGRaPH 



257 



recording lever of the Crescograph traces a horizontal line 

 on the moving plate. Overbalance or underbalance will 

 deflect the record below or above the horizontal line. 



COMPENSATING MOVEMENT, 



For securing exact balance the holder of the plant P, in 

 the given example, will have to subside at a rate of ^~^ 



SG 



Fig. 93. — Arrangement for compensation of growth-movement by equal subsi- 

 dence of plant-holder; S, adjusting screw for regulation of speed of rotation; G, 

 governor; W, heavy weight; P, plant-holder. 



inch per second. This is accomplished by a system of 

 reducing worm and pinion, also of clock wheels (Fig, 93), 

 The clock at first used for this purpose was worked by 

 the usual balance wheel. Though this secured an average 

 balance yet as each tick of the clock consisted of sudden 

 movement and stoppage, it caused minute variation in the 



